Conventionally, for an image forming apparatus, when sample printing is executed to check the text configuration, the layout, etc., of the printing result, printing is executed always putting higher priority on the printing speed than the image quality as seen in, for example, Japanese Laid-Open Patent Publication No. H02(1990)-235137.
A method of executing sample printing executed for the case where color pages and monochrome pages are mixed can be a method according to which it is specified to print either color pages or monochrome pages at one time together and, thereby, the throughput is improved and the processing speed of the sample printing is increased as, for example, the invention described in Japanese Laid-Open Patent Publication No. 2001-103318.
However, according to the invention described in Japanese Laid-Open Patent Publication No. H02-235137, printing is executed according to a so-called “speed priority printing scheme” that increases the printing speed by degrading uniformly the image quality even when pages that are desired to be checked on the image quality thereof in high image quality is included in the sample printing and, therefore, a problem has arisen that, when pages that need to be checked on the image quality thereof are included, the check can not be executed.
According to the invention described in Japanese Laid-Open Patent Publication No. 2001-103318, though the throughput during the sample printing is improved, the processing speed is not increased so much compared to the speed priority printing scheme of printing with degraded image quality. However, when printing is executed in the speed priority printing scheme with uniformly degraded image quality admitting the above, a check on the image quality of color pages and pages with photos can not be executed.